From forums:
“How to get to 60 fast?
Well start with Spirit tap, and then go over at Unbreakable will and then build up Improved Power word: Shield.
Spirit tap: 5/5
Unbreakble will: 5/5
Improved Power word: Shield: 5/5
After that build further on the Shadowtree, get the talents Mindflay, improved shadowword pain and improved Mind Blast first. The best mob to grind is the one with low hp. Thats usually Clothuser humanoids, but I’ve also met creeps living at the sea that have low hp (the Shattered strand Azhara).
In level 40 you respecc to Shadow Form, and then you should speed up the grinding.
And have a nice wand at your hand the whole time :)”